Abstract: :
Purpose: Our studies aim to dissect the potential involvementof complement components during lens regeneration in the adultnewt. We selected this urodele model because of its abilityto regenerate its lens as an adult. Complement components area family of molecules that play a crucial role in innate immunity.However, recent studies have suggested that complement componentsmay play diverse and rather unconventional roles in severaldevelopmental and regenerative processes by modulating celldifferentiation and promoting cell-cell interactions. It hasbeen previously shown that C3 is expressed in the regeneratingblastema of the amputated limb in urodeles, thus implicatingcomplement as a critical mediator in regenerative pathways involvingtransdifferentiation and pattern formation (Del Rio-Tsonis etal., J. Immunol., 1998). These studies have now been extendedto the lens regeneration model in urodeles and aim to elucidatethe role of C3 and C5 complement molecules in this process.Methods:In situ hybrization and Immunohistochemistry usingspecific antibodies against C3 and C5 were used as tools tostudy the expression pattern of these molecules during lensregeneration. In addition, we used Cobra Venom Factor (CVF)to interfere with the complement pathway in vivo and examineits effects on lens regeneration.Results: Expression studiessuggest that both C3 and C5 mRNA are produced by the cells ofthe dorsal iris that transdifferentiate to form the new lens.The protein expression data also shows that C3 and C5 are expressedin the eye during lens regeneration. Studies to assess the possible"in vivo" role of complement in regeneration are underway andwill be discussed.Conclusions: Our results indicate that Complementcomponents C3 and C5 are expressed during lens regenerationand that they might be implicated in the regulation of thisprocess.